Shears



10, 1936. F. M. WHYTE v 2,033,216

SHEARS Filed Feb. 20, 1935 ATTORNEYS Patented Mar. 10, 1936 TNT ICE

1 Claim.

This invention relates more particularly to improvements in shears ofthe type disclosed in my copending patent application Serial No.671,811, filed May 19, 1933. In that type of shears the coactiveshearing members have mutual bearing contact at three points only intriangular arrangement around the axis of the pivotal connection betweensaid members to obtain effective shearing coaction of the blades.

An important object of the present invention is to provide asatisfactory embodiment of said three-point bearing contact feature inshears for cutting tin or other sheet material and more particularly toprovide such an embodiment designed to prevent objectionable spreadingand bending of the sheet material as the shears are passed therethroughin the act of cutting it.

Other objects of the invention will appear hereinafter.

In the drawing:

Fig. 1 is a side view of the improved tin shears;

Fig. 2 an opposite side view of the forward portion of the shears;

Fig. 3 an inner face view of one of the blades;

Fig. 4 an inner face view of the other blade;

Fig. 5 an enlarged transverse section on the line 55 of Fig. 1; and

Fig. 6 an edge view of the forward portion of the shears.

The shears include companion blade and handle members I and 2, pivotallyconnected. Said members have similar handle portions each with a shank 3and a handle loop l. Preferably the handle loops of both members areelongated to facilitate grasping of the loops for use of the shears ineither the position shown in Fig. 1 or in an inverted position. Eitherloop will acco'mmodate either the thumb or the fingers. The loops haveopposed stop lugs 5 disposed to abut and limit the closing of theshears. Other stop means, differently located may, however, be employedin lieu of that shown.

The member I has a blade portion I and a medial hub portion I Both arerather wide in the present instance. The member 2 has a blade portion 2and a medial hub portion 2 both, in the present instance, rather narrowin comparison with the corresponding portions of the member I. The hubportions I and 2 are overlapped and have registering apertures 5. Apivot bolt I extends loosely through said apertures and has a headbearing against the outer face of the member I, and a nut 8 screwedthereon in a position spaced outward from the outer face of the member2. A washer 9 encircles the bolt and bears against the outer face of themember 2, and a coiled compression spring III is interposed between thenut and washer to hold the members I and 2 under compression andmaintain the three-point contact therebetween, 5 r

also flat and smooth and its outer margin, rear- Ward of the pivot,forms a bearing surface for one of the aforesaid three contact pointsbetween the members I and 2. The hub portion I is integrally formed withan extension or ear I3 extending transversely outward beyond the cuttingedge. Said ear is flat and parallel to the plane of the body of the hubI and it is disposed in an inset position. Its outer face I4 is disposedapproximately in the plane of the blade marginal surface II and itsinner face I5 is in relief with reference to the inner face of the hub.The rear edge of the ear and that of the body of the hub are on an arcstruck from the pivot aperture 6 as a center. The forward edge of theear inclines forward and inward toward the cutting edge of the blade.The inner face I5 of the ear is flat and smooth and the margin thereofalong said are forms a bearing surface for another of the aforesaidthree bearing contacts. Along the base of the ear the adjacent edge ofthe body of the hub portion forms a smooth ledge I6. The latter extendsalong a straight line leading from the inner end of the cutting edge ofthe blade, rearward past the pivot and the ear and ends at the outeredge of the handle shank 3. The longitudinal line of the ledge is atonly a slight angle to the cutting edge and it passes rather close tothe pivot.

Referring to the blade and handle member 2, the blade 2 thereof has themargin I1 of its cutting edge raised or in relief upon the inner face ofthe blade. Rearward of the cutting edge the inner face of the medialportion of the member 2 is recessed to depress an area I8 of the faceand afford clearance for the raised inner surface of the extension IS onthe companion member I. At one side, the area I8 is bounded by an edgeI9 of the medial portion. Said edge extends from the rear end of thecutting edge, rearward along a straight line at a slight angle to thecutting edge and leading to the outer edge of the shank 3. Saidline-extends rather closely past the pivot. Within the depressed area I8the hub 2 has an integral bearing projection 20. The latter is locatedat a point materially rearward of the pivot aperture 6 and at oradjacent to the edge I9. It makes a wiping bearing contact with theopposed surface I2 on the companion member I and thereby establishes oneof the aforesaid three points of mutual bearing contact between themembers I and 2.

The member 2 at its back edge, opposite the edge I9, has a flat,integral ear 2| in opposed relation to the ear I3 on the companionmember I. Said ear 2| is outwardly ofiset to space its inner face awayfrom the opposed face I5 of the ear I3. It is located at a pointintermediate the pivot aperture 6 and the bearing projection 20,longitudinally of the member 2, and has a central aperture 2 I. Theaperture is spaced transversely outward a material distance from thepivot aper-' ture 6. A bearing element in the form of a stud 22 has asubstantially cylindrical head disposed between the opposed ears I3 and2I, and a reduced shank removably fitted in the aperture 2|. The head ofthe stud makes wiping bearing contact with the opposed face I5 of theear I3 to establish another of said three points of mutual contactbetween the members I and 2.

In the assembled shears the pressure exerted by the spring I 9 aroundthe pivot compresses the members I and 2 toward each other, to presstogether the blades at a point on the margins of the cutting edges,press the bearing projection 20 against the bearing track surface I2 andpress the head of the bearing stud 22 against the bearing track surfaceI 5. Thereby the three points of mutual bearing contact are established,and the contact at the three points is maintained by the spring. Onepoint of contact is at the margins of the cutting edges of the bladesand moves inward and outward along said margins as the shears are openedand closed respectively. A second point of contactis determined by thelocation of the bearing projection 20. It is located in substantialalinement with the cutting edge of blade 2 and is spaced materiallyrearward of the pivot. The third point of contact is determined by thelocation of the bearing stud 22, spaced transversely materially outwardfrom the pivot.

The three contact points are in triangular arrangement around the pivotand at all other points on their opposed faces the members I and 2 areout of contact. The point of contact at the blade margins coincidesalways with the shearing point as it advances and recedes along theblades, and the spring pressure maintaining the contact at said pointensures effective shearing coaction of the blades. The shears can beoperated easily and effectively by the left hand as well as the righthand. The spring will hold the blades in contact for shearing withouteffort or care on the part of the user.

To further improve the shearing coaction there is preferably maintaineda slight transverse tilt between the blades. As shown in Fig. 5, thedepth of the head of the stud 22 is sufiicient to hold the member 2canted slightly with reference to member I so that its blade margin I'Iwill be tilted slightly on the blade margin II. Should the head weardown in service, the desired degree .of tilt may be restored by placinga shim or washer between the shoulder of the stud 22 and the ear 2I. Thedegree of tilt is thus governable at this point of contact but isnon-governable at the other two points. By restricting the adjustment toone point confusion in adjustment is avoided.

The desirable three point contact feature in its present embodimentenables the shares to easily cut tin or other sheet material withoutobjectionably spreading apart and bending the sections of the severedmaterial at opposite sides of the shears as the shearing operationprogresses through a sheet. The three point contact and tilted bladefeature involves an increase in the width of the shears at their medialportions in order to render said feature properly effective. The presentinvention enables this feature to be employed to full advantage andavoids the necessity of objectionably bending the severed sections ofsheet material to pass over the wide hub structure. Fig. 2 shows theacute angle made by the guide ledge I6 on the member I and the guideedge IS on the member 2 and indicates the rather slight degree ofdivergence the two sections of severed material will have when theshears are closed.

At one side of the shears one section of the sheet is guided by the edgeI9 on the member 2 to pass rearward there along closely past the pivotand at only a slight angle to the cutting edge of the blade 2*. Thissection of the sheet is also guided by the vertical surface I2 on theother member I. Thus at one side of the shears one section of thesevered sheet is guided by both members I and 2. At the opposite side ofthe shears, however, by reason of the peculiar design of the hub memberI in which the ear I3 is inset from the body of the hub, the othersection of the sheet material is enabled to pass rearward along theguide ledge I6, and it is guided by said ledge and also by the verticalsurface I4. The guide ledge I6 and the guide surface I4 are both on themember I. Hence the section of material at this side of the shears isguided solely by the member I. Since the ledge I6 is disposed at only aslight angle to the cutting edge of blade I and extends between theoutwardly spaced bearing contact point and the pivot, and close to thelatter, the sheet material is enabled to pass rearward with minimumbending. Thereby injury of the material is prevented and resistance tooperation of the shears is reduced.

The structure of the hub portions of the members I and 2 also providesthem with integral stops to limit the opening movement of the shears.The inclined forward edge of the ear I3 is disposed to abut a transverseshoulder 23 joining the inner surface of the blade 2 and the depressedsurface I8 when the shears are opened to the allowable maximum.

"What I claim is:

Shears in which coactive blade and handle members have medial portionsthereof overlapped and pivotally connected and wherein said members havemutual bearing contact at three points only in triangular arrangementaround the pivot axis, with one of said points at the margins of thecutting edges of the blades, another of the points spaced longitudinallyrearward from the cutting edge of one of said members and the thirdpoint spaced transversely toward the back edge of said member a materialdistance outward from the pivot axis, characterized in that the other ofsaid members has an edge marginal extension to form part of the bearingcontact at said third point and has its outer face inset for the purposeset forth and disposed approximately in the plane of the cutting edge ofthe member and its inner face in relief from the cutting plane at theinner face of the member and the member has an outer guide ledge alongthe root of said extension and extending from the cutting edgelongitudinally rearward closely past the pivot to guide severed materialpast the pivot and avoid objectionable bending of the material in orderto pass over said third point of contact, and the companion 10 member isrecessed at its inner face to afiord clearance for said marginalextension and has a back edge extension opposed to said first extensionand outwardly offset to provide clearance between said opposedextensions and has a removable contact element between said extensionsfor Wiping bearing contact with the inner face of said first extensionto establish said third point of bearing contact.

FREDERICK M. WHYTE.

